As part of attempts to improve selection among south-eastern Australian benthic fish trawls, an experiment was done to assess: (1) for confounding effects of a narrower-than-recommended hooped cover over a conventional trawl codend; and then (2) the associated size selection of eastern school whiting, Sillago flindersi; and (3) if this could be improved by inserting a large panel of smaller square-shaped mesh. The narrow cover was required to avoid contacting the seabed and did not affect trawl wing-end spread or catching efficiency. Despite a stretched mesh opening (SMO) of 96 mm and much larger than all S. flindersi (11–26 cm total length; TL), the conventional codend had a low 50% size at retention (L₅₀) of 16.8 cm TL (selection range of 5.9 cm), which was close to the minimum marketable length. The capture of small S. flindersi by the large-meshed codend was attributed to an excessive increase in circumference (from 100 to 200 meshes) and a legally permitted ‘catch-separating’ rope to restrict fractional mesh openings to <~21%. Replacing ~1/4 of the 96-mm SMO netting in the codend and anterior extension with a panel of square-shaped mesh (~42-mm SMO hung on the bar) marginally (p = 0.065) improved size selection for S. flindersi (by allowing some fish <~15 cm TL to escape). Increasing the size of mesh in the panel to ~47 mm hung on the bar might allow more smaller S. flindersi to escape. But using a smaller mesh size throughout the entire codend, concurrent with other gear or spatio-temporal controls when targeting S. flindersi might be a more coherent management option than retroactively handicapping the existing large-mesh codends.

作为改善澳大利亚东南部底栖鱼拖网选择的尝试的一部分，进行了一项实验以评估：（1）比推荐的环盖窄于传统拖网编码的混杂影响；然后（2）东部学校鳕鱼、Sillago flindersi的相关尺寸选择；(3) 是否可以通过插入一大块较小的方形网格来改善这种情况。要求狭窄的覆盖物避免接触海床，并且不影响拖网翼端展开或捕获效率。尽管拉伸网孔 (SMO) 为 96 毫米，并且比所有S. flindersi (11-26 厘米总长度; TL) 大得多，但传统的 codend 在保留时具有低 50% 的尺寸 (L ₅₀) 的 16.8 厘米 TL（选择范围为 5.9 厘米），接近最小可销售长度。大网眼密码对小型S. flindersi的捕获归因于周长过度增加（从 100 到 200 目）和法律允许的“捕获分离”绳索，以将分数网格开口限制在 <~21%。用方形网片（约 42 毫米 SMO 挂在杆上）略微 ( p = 0.065) 改进S. flindersi 的尺寸选择（通过允许一些 <~15 cm TL 的鱼逃脱）。将面板中的网格尺寸增加到悬挂在杆上的 ~ 47 mm 可能会允许更小的S. flindersi逃离。但是，在针对S. flindersi时，在整个 codend 中使用较小的网格尺寸，与其他齿轮或时空控制同时进行，可能是比追溯限制现有的大网格 codends 更连贯的管理选项。